ML20137Y500
| ML20137Y500 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 09/24/1985 |
| From: | Edelman M CLEVELAND ELECTRIC ILLUMINATING CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| (RDC-123(85)), PY-CEI-OIE-0112, PY-CEI-OIE-112, NUDOCS 8510080019 | |
| Download: ML20137Y500 (3) | |
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l THE CLEVELAND ELECTRIC ILLUMIN ATING COMP ANY P.O. BOX 5000 - CLEVELAND, OHIO 44101 - TELEPHONE (216) 622-9800 - ILLUMINATING BLDG - 55 PUBLIC SQUARE Serving The Best Location in the Nation MURf%Y R. EDRMAN VICE PRESIDENT WUC EAR September 24, 1985 PY-CEI/OIE-0112 L Mr. James G. Keppler Regional Administrator, Region III Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137 RE:
Perry Nuclear Power Plant Docket Nos. 50-440; 50-441 Overpressurization of Isolated Volumes in Drywell Post-LOCA [RDC 123(85)]
Dear Mr. Keppler:
This letter serves as our final report pursuant to 10CFR50.55.(e) on the potential design deficiencies associated with drywell over-pressurization which could affect certain components in a post-LOCA (Loss of Coolant Accident) environment.
Mr.
J. McCormick-Barger was first notified on December 13, 1984, by Mr. T. A. Boss of The Cleveland Electric Illuminating Company (CEI) that this problem was being evaluated per Deviation Analysis Report (DAR) 218.
Our interim report was filed with your office on January 10, 1985 and two letters were filed on April 12 and June 7, 1985 to advise you of our progress.
Description of Deficiency The drywell area in the reactor building contains four isolated piping volumes which are unprotected by pressure relief devices.
The B21 system and door seals for the drywell personnel airlock are primarily affected.
It has been determined that the original design for the piping and components related to these four volumes did not consider worst case pressures due to post-LOCA temperature excursions.
This resulted in underestimation of the design pressure of these components in the drywell in a post-LOCA environment.
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,Mr. J. G. Keppler Septembsr 24, 1985 PY-CEI/OIE 0112 L Analysis of Safety Implications The analysis of the worst case overpressurization of the isolated volumes in the drywell, during a post-LOCA, identified the potential that certain B21 components and the personnel airlock seals may be unable to perform their intended safety function, and that certain isolated piping volumes could be overstressed by the pressures resulting from post-LOCA temperatures.
In addition, the ADS-SRV's and the valves controlling the air supply to and from the Main Steam Isolation Valves (MSIV) may not be able to operate properly due to the higher airline pressure.
The Unit 1 drywell personnel airlock seals had the potential to fail ts described in DAR 147.
Corrective Action As stated in our interim report to your office on January 11, 1985, Gilbert / Commonwealth, Inc. (G/C Inc.), our Architect / Engineer, performed an analysis of the design with the worst case temperature excursions and resultant pressures.
The analysis indicates that the B21 piping for the isolated volumes in the drywell area will not be overstressed by the pressures resulting from post-LOCA conditions.
General Electric completed their evaluation of the effects of in-creased pressures on the Automatic Depressurization System Safety Relief Valves (ADS-SRV's).
Results of the evaluation indicated that the ADS-SRV's and also the non-ADS-SRV's, will operate properly at the worst case pressures postulated post-LOCA.
The higher drywell temperature may cause a pressure build-up in the MSIV accumulators.
General Electric has determined that this pre-sents no problem since the NORGEN air valves and the MSIV air cylinder were designed and tested to 300 psi internal pressure.
Operation of the ASCO solenoid valves could not be guaranteed at these higher post-LOCA pressures as these valves are rated only for 125 psi.
To provide assurance that the ASCO solenoid valves would operate as designed, Engineering Change Notice 28386-86-2189 was implemented to provide a relief valve which will prevent the line pressure from exceeding 125 psi.
Finally, as stated in our letter to your office on June 7, 1985, che resolution of the problem concerning the Unit 1 drywell personnel airlock seals and associated inflation system was completed through the corrective action taken for DAR 147.
Please call if there are any questions.
Sincerely, Atte W
Murray
. Edelman Vice President Nuclear Group MRE:sab i
es G. Keppler September 24, 1985 PY-CEI/OIE 0112 L cc:
J. A. Grobe USNRC Site Office Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C. 20555 U.S. Nuclear Regulatory Commission Document Control Desk i
Washington, D.C.
20555 Records Center, SEE-IN Institute of Nuclear Power Operations l
1100 Circle 75 Parkway, Suite 1500 Atlanta, Georgia 33039 i
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